title: SGEBP, a giant protein from starfish oocytes able to interact with ERK.
abstract: The mitogen-activated protein kinase (MAPK) pathway is a key regulator of animal meiotic divisions. It involves cascades of kinases whose specificity has been shown to depend on binding proteins acting as scaffolds. We searched for proteins interacting with starfish extracellular signal-regulated kinase (ERK) using the yeast two-hybrid system. An interacting clone was found to encode the 5' region of a giant 16.7-kb transcript encoded by an intronless gene. The corresponding 630-kDa protein could not be detected by Western blot, but the meiotic spindle was labelled by immunolocalization with an antibody against the ERK-binding domain. A related gene was found in the genome of another starfish species, and similarities were also found to a 42.9-kb open reading frame in the sea urchin genome. Yet, no conserved protein-binding domain was detected in the amino acid sequence(s) compared to all the known motifs. Structure prediction software indicated that the encoded proteins are probably disordered while a query of the disordered protein database indicated some similarity with vertebrates microtubule-associated protein 2 (MAP2). This predicts that SGEBP may function as a space-filling polymer, having a role in both cytoskeleton organization and ERK targeting.
authors.affiliation: UPMC Univ Paris 06, Laboratoire Arago, Avenue Fontaulé, BP44F-66650, Banyuls/mer, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Vergé
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Lozano
authors.forename: Philippe
authors.initials: P
authors.lastname: Schatt
authors.forename: Gérard
authors.initials: G
authors.lastname: Peaucellier
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000235:genetics; D012617:Sea Urchins / Q000378:metabolism; D020539:Sequence Analysis, Protein; D013215:Starfish / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D002352:Carrier Proteins; D008869:Microtubule-Associated Proteins; D012333:RNA, Messenger; D048049:Extracellular Signal-Regulated MAP Kinases
keywords: MAP kinase; echinoderm; giant protein